Sheltered in four doors, people grow only to know, what to them is shown, what is always right or wrong... but as they grow they find out that not everything falls into those two ways, sometimes there is a path in between, the loopholes to the rules they have come to know... You have described it so good in words... the shock of going to the outside world... when the curtains rise and show... the truth about what life is.

This piece is so touching. The portrayal itself is innocent. I can see it all being played out before my own eyes. This is one of my great fears, for myself & others. It makes you feel helpless to this change, helpless you can't protect them forever. Helpless to not know how much damage was caused. This is how we all grew & learned, this is how we experienced life. The importance of innocence is only realized after it has gone for a long time.

"Innocent souls raised behind a closed door.
Where black and white are so easily differentiated."

I like the idea of a closed door, if the door is not a physical one. I can picture a sweet door of iceor something, but for me a door like wood represents unpleasant and harsh strictness. I don't think that fosters true innocence. The door, however, is being pushed earlier and earlier these days. Black and white are not the best words to use here because they can imply other things than what you mean, like race; so something like "stained and pure" would be better in my opinion.

"As dawn calls the children,
As they sing there seemingly everlasting songs.

Joyous they gleam
Stainless they seem."

does dawn represent growing up? Children so look forward to growing up. They are always dreaming, or singing about it--and are so happy for its arrival. Those already grown up might find them cute, and still marvel how innocence they are.

"When opening the door became inevitable.

Their elders contended to warn
Their elders began to mourn"

So the elders mourn and warn. Indeed! When the time actually comes, the elders know from experience the true bitterness behind that door. I imagine they worry much.

"As they took it so lightly
As they so fervently yearned away.

They rushed
to see new sights!
to feel the new world!

Curiously
Carelessly"

This is what the elders fear. I love this part. You chose the right words--They rushed to see the new sights, to feel the new world--curiously, carelessly. It's so good I hardly know what to say. Musical.

"When fear struck and sickened their hearts
Their black and white merging
So hard to tell apart!"

I thought this part was a little unclear. Is it that fear struck when they longer could tell the two apart, or because of fear they could not tell them apart? Could be clarified. I think that the fear comes after they find they cannot tell the two apart. And, consider changing black and white.

"When the innocent's innocence drained.
Just as they were so fervently wishing,
Unknowingly

Grey consumed their vision."

Okay, this introduction of gray is beautiful in relation to using colors black and white, but still. Innocence drained--just as they were wishing--unknowingly...that is deep.